Drying roll



H. P. FRY, JR

May 21, 1957 DRYING ROLL Filed Feb. 18, 1955 United States Patent DRYING ROLL Horace P. Fry, Jr., West Chester, Pa., assignor to American Viscose Corporation, Philadelphia, Pa., 2 corporation of Delaware Application February 18, 1955, Serial No. 489,095 11 Claims. (Cl. 34-124) The present invention relates to a drying roll which may be used for drying a continuously traveling sheet of flexible material such as cellophane. In particular, the invention relates to a drying roll which, when heated to a drying temperature maintains a temperature differential between the end and central surface portions of the roll.

In the production of continuous sheets of flexible ma terial, such as cellophane, it is the general practice to dry the wet sheets by passing them over a series of rotating hollow rolls which are internally heated by a suitable heating medium such as steam or hot water. The roll surfaces are of substantially uniform temperature and because of this factor many difliculties and disadvantages are encountered which tend to produce sheet products of inferior quality. For instance, when drying cellophane uniform temperature rolls, it has rapidly than the central portlon of the film whereby the final sheet has a non-uniform moisture content, the edge.

portions having less moisture than the central portions of the sheet. As a result of this non-uniform drying pattern the sheet edge portions shrink more rapidly than the central portions of the sheet whereby the final film or sheet has curly or floppy causing damage to the sheet. Obvious difficulties are encountered when using such a sheet of non-uniform strength and moisture content in wrapping machines,

packaging machines, multicolored printing machines, etc.

Therefore, it is one object of my invention to provide Another object of my invention is to provide a drying roll wherein a temperature differential is maintained be tween the end and central portions of the roll surface.

Still another object of my invention is to provide a drying drum wherein the heat transfer between the heating medium within the drum interior and the end surface portions of the roll is substantially retarded.

Other objects and advantages will become more apparent from a study of the following description and draw ings wherein:

Figure 1 is a section of the ternal make up of the roll;

Figure 2 is a perspective of the sleeve member mounted within and at each end of the roll of Figure 1; u

'drying roll showing the inedges which are easily torn or ripped to overcome the difficulties water, or other suitable heating medium 2,792,642 Patented May 21, i957 Figure 3 is a detail in section of one end of the roll showing a modification of the roll of Figure 1;

Figure 4 is a detail in section showing an embodiment of the roll structure of Figure 1; and

Figure 5 is a detail in section showing an embodiment of the roll structure of Figure 3.

Briefly my drying roll comprises a hollow drum with end supports for journaling the drum in a suitable frame. Extending within the drum interior is a heating medium feed conduit or pipe. The feed conduit extends through one of the end supports and is preferably journaled in the opposite end support. Conical sleeves are mounted within the drum interior at each end thereof in such a manner as to provide an insulating air layer between the sleeve wall and the inner modification of the above, the drum surface itself may be constructed in such a manner that the insulating air layers may be formed without the use of the conical sleeves. The insulating air layer retards the heat transfer between the heating medium introduced within the drum interior and the end surface portions of the roll.

Referring now to the drawings, my drying roll A comprises a hollow metal drum 1 having end supports 2 and 3 for journ aling the drum 1 in suitable vertical frame supports. The roll A is driven through a drive gear assembly 4 afiixed to the end support 2. To conduct steam, hot

to the interior of the drum 1, a heating medium feed pipe 5 extends through end support 2 and is journaled in opposite end support 3 whereby it remains stationary and does not rotate with the roll A. The feed pipe 5 is connected with a suitable heating medium supply assembly (not shown) which is positioned externally of the drum. A plurality of spaced apart holes or openings 8, 8 extend wall Within the drum interior wherewhile the larger diameter end of each sleeve contacts the inner surface of the drum at 20, 20.

Since the sleeves 15, 15 are rolled with the ends overlapped, they have a and larger ends of the sleeves are slightly larger than the diameters of the shoulders 18, 18 and of the more central portion of the drum The temperature of the central drum 1 will, therefore, be higher surface of the drum. As a 3 arate which is slower than that of the, more. central portion of the sheet whereby the film edges will dry at substantially the same uniform rate as the central portions of the sheet. The sleeves 15, 15 are, of course, installed before the end supports 2 and 3 are secured to the drum.

In Figure 3 there is shown a modification of a drying roll described above. The drum 25 is constructed so that the end surface portions 26 (only one being shown) of the drum taper inwardly toward the drum axis. The end portion 26 is seated within an annular ring notch 27 in the end support 28 and an annular seal 29 of rubber or other suitable material is supported within notch 27 whereby the interior of the drum is sealed off from the atmosphere. A sleeve 30 of the same diameter as that of the central portion of drum 25 is seated at one end against an annular shoulder 31 of drum 25 which shoulder is formed by the drum surface at the point of initial taper of the tapered end surface portion 26. The opposite end of the sleeve 30 is secured to the end support 28 by screw 32 or other suitable securing means to form an extension of the drum surface whereby a closed-off or insulating layer is provided between the drum interior and the drum surface adjacent the end portions of the drum 1. This end drum structure is, of course, duplicated at the opposite end of the drum 25.

If desired, a suitable amount of mineral wool or other suitable insulating material 34 may be inserted within the closed-off space between the conical sleeves 15, 15 and the inner surface of the drum 1 (Figure 4) or within the space between the tapered drum ends 26, 26 and the sleeves 30, 30 (Figure With the use of a suitable insulating material, the heat transfer exchange is, of course, further retarded between the end surface portions of the drum and the heating medium within the drum. It should be pointed out that the end surface portions of the drum will be of a sufficient temperature, although of a lower temperature than the central surface portions of the drum, to properly dry the edge portions of the sheet traveling over the drum since heat transfer, to a certain degree, occurs between the central surface portions of the drum and the end surface portions thereof. In addition, some heat transfer is effected through the insulating layers described above.

It is to be understood that changes and variations of the present invention may be made without departing from the spirit or scope of the present invention as defined in the appended claims.

I claim:

1. A drying roll for uniformly drying a continuously traveling sheet of flexible material comprising a drum, a heating medium feed pipe extending through one end of the drum, and means at each end of the drum which cooperate with the drum interior to provide an insulating layer of air at each end of the drum interior whereby the insulating layers at the drum ends reduce the heat transfer between the heating medium and the end surface portions of the drum to create a temperature differential between the end and central surface portions of the drum.

2. A drying roll for uniformly drying a continuously travelling sheet of cellophane according to claim 1 comprising insulating material positioned within the insulating air layers.

3. A drying roll for uniformly drying a continuously traveling sheet of flexible material comprising a drum, end supports for the drum, a heating medium feed pipe extending through one end support and journaled in the opposite end support, and an imperforated sleeve member positioned within the drum interior at each end thereof which sleeves cooperate with the end portions of the inner surface of the drum to provide an insulating layer of air at each end of the drum interior whereby the insulating layers at the drum ends retard the heat transfer between the heating medium and the end surface portions of the drum to create a temperature differential between the end and central surface portions of the drum.

. 4. .A drying rollfor uniformly drying a continuously traveling sheet of cellophane according to claim 3 comprising insulating material housed between the sleeve and the inner surfaces of the drum.

5. A drying roll for uniformly drying a continuously traveling sheet of cellophane comprising a drum, end supports for the drum, a heating medium feed pipe extending through one end support and journaled in the opposite end support, and an imperforated conical sleeve positioned within the drum interior at each end thereof which sleeves cooperate with the end portions of the inner surface of the drum to provide an insulating layer of air at each end of the drum interior whereby the insulating layers at the drum ends retard the heat transfer between the heating medium and the end surface portions of the drum to create a temperature differential between the end and central surface portions of the drum.

6. A drying roll for uniformly drying a continuously traveling sheet of flexible material comprising a drum, inwardly extending shoulders on the inner surface of the drum at the extremities thereof, a heating medium feed pipe extending through one end support and journaled in the opposite end support, and a conical metal sleeve positioned within the drum interior at each end thereof, the larger diameter end of each sleeve contacting and forming a seal with the inner surface of the drum, and the smaller diameter end of each sleeve contacting and forming a seal with one of the shoulders at the drum extremities whereby an insulating layer of air is provided at each end of the drum which reduces the heat transfer between the heating medium and the end surface portions of the drum to create a temperature differential between the end and central surface portions of the drum.

7. A drying roll for uniformly drying a continuously traveling sheet of cellophane according to claim 6 wherein the conical sleeve comprises a rolled conical sleeve.

8. A drying roll for uniformly drying a'continuously traveling sheet of cellophane according to claim 6 comprising metal conical sleeves which are welded to the inner surface of the drum.

9. A drying roll for drying a continuously traveling sheet of cellophane comprising a drum having end surface portions which taper inwardly toward the drum axis, end supports for the drum, an annular notch in the inner side of each end support which seats the edge of the tapered surface portion of the drum, a sleeve positioned over each tapered end of the drum, said sleeves being of the same diameter as that of the untapered drum surface portion whereby it forms a portion of the drum surface over which the cellophane travels, and means for securing each sleeve to one of the end supports to form an insulating layer of air between each sleeve and the tapered surface portions of the drum whereby the insulating layers at the drum ends reduce the heat transfer between the heating medium and the end surface portions of the drum to create a temperature differential between the end and central surface portions of the drum.

10. A drying drum for uniformly drying a continuously traveling sheet of cellophane according to claim 9 comprising sealing rings within the ring notch.

11. A drying roll for uniformly drying a continuous traveling sheet of cellophane according to claim 9 comprising fibrous insulating matter housed within the space between the tapered end portions of the drum and the sleeves positioned over the tapered portions.

References Cited in the file of this patent UNITED STATES PATENTS 1,693,934 Millspaugh Dec. 4, 1928 1,884,727 Kermer Oct. 25, 1932 FOREIGN PATENTS 262,704 Great Britain Dec. 16, 1926 

